1. Field of the Invention
The invention is directed to a brush holder having at least one carbon holder which forms a guide for a carbon brush and at which a holding spring is provided, which holding spring presses the carbon brush against a first guide side of the guide with a holding pressure.
2. Description of the Prior Art
In brush holders of the type mentioned above, vibrations which occur during operation, can cause the carbon brushes to tilt relative to the carbon holder due to movement play. This movement play must be preserved in order to allow the carbon brushes to move along the guide. As a result of the tilting and movement play, increased wear can occur in some areas at a contact surface and at the surfaces which contact the carbon holder. In a brush holder of the type mentioned above, the tilting and resulting wear can be appreciably reduced by pressing the carbon brushes against the guide side.
U.S. Pat. No. 3,526,797 discloses a carbon holder at which a spring arrangement is held in a swivelable manner. The spring arrangement has a rolled flat spring which presses against a front side of a carbon brush remote of the commutator by a rolled portion in a clamping position in order to bias this carbon brush against the commutator. At the same time, a curved area at a free end of the flat spring presses the carbon brush against a guide wall of the carbon holder.
The drawback of the known carbon holder consists in that the spring arrangement has a very complicated shape which in turn requires a special receptacle at the carbon holder. This results in very high overall production costs for the brush holder. Further, the curved area which presses laterally against the carbon brush generates a line tension which cuts into the carbon brush increasingly due to vibrations occurring in operation.